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Influence of Fe2O3 and bacterial biofilms on Cu(II) distribution in a simulated aqueous solution: A feasibility study to sediments in the Pearl River Estuary (PR China)

Kurniawan TA, Lo W, Othman MHD, Liang X, Goh HH, Chew KW

J Environ Manage, 2023 Mar 01;329:117047.
PMID: 36563449 DOI: 10.1016/j.jenvman.2022.117047

This study investigated physico-chemical interactions among Cu(II), biogenic materials, and Fe2O3 in a continuous-flow biofilm reactor system under a well-controlled environment. The effects of Fe2O3 and bacterial biofilms on the distribution of Cu(II) in a simulated aquatic environment were studied. To control biological and abiotic elements in the marine environment, a biofilm reactor was designed to understand the metal speciation of Cu(II) and its distribution. The reactor consisted of a biofilm chamber equipped with glass slides for biofilms attachment. Due to its ability to grow as biofilm in the medium, Pseudomonas atlantica was cultivated to adsorb trace Cu(II) to attached and suspended cells. It was found that biofilms with 170-285 mequiv chemical oxygen demand (COD) concentration/m2 of total oxidizable materials accelerated the Cu(II) adsorption to the surface of the reactor significantly by a factor of five. A significant inhibition to the bacterial growth took place (p ≤ 0.05; t-test) when Cu(II) concentration was higher than 0.5 mg/L. In the absence of Cu(II), bacterial cells grew normally to 0.075 of optical density (OD). However, at the Cu(II) concentration of 0.2 mg/L, the cells grew to a lower OD of 0.58. The presence of glycine and EDTA substantially reduced the toxicity of Cu(II) on bacterial growth (p ≤ 0.05; paired t-test). Their complexation with Cu(II) rendered the metal ions less available to bacterial cells. This implies that the Fe2O3 and bacterial biofilm affected Cu(II) distribution and speciation in the aquatic environment.

Matched MeSH terms: Biofilms
Fulltext In Vitro Assessment on Designing Novel Antibiofilms of Pseudomonas aeruginosa Using a Computational Approach

Rachmawati D, Fahmi MZ, Abdjan MI, Wasito EB, Siswanto I, Mazlan N, et al.

Molecules, 2022 Dec 15;27(24).
PMID: 36558064 DOI: 10.3390/molecules27248935

An anti-biofilm that can inhibit the matrix of biofilm formation is necessary to prevent recurrent and chronic Pseudomonas aeruginosa infection. This study aimed to design compounds with a new mechanism through competitive inhibitory activity against phosphomannomutase/phosphoglucomutase (PMM/PGM), using in vitro assessment and a computational (in silico) approach. The active site of PMM/PGM was assessed through molecular redocking using L-tartaric acid as the native ligand and other small molecules, such as glucaric acid, D-sorbitol, and ascorbic acid. The docking program set the small molecules to the active site, showing a stable complex formation. Analysis of structural similarity, bioavailability, absorption, distribution, metabolism, excretion, and toxicity properties proved the potential application of ligands as an anti-biofilm. In vitro assessment with crystal violet showed that the ligands could reach up to 95.87% inhibition at different concentrations. The nitrocellulose membrane and scanning electron microscopic visualization showed that the untreated P. aeruginosa biofilm was denser than the ligand-treated biofilm.

Matched MeSH terms: Biofilms
Mechanistic behaviour of Chlorella vulgaris biofilm formation onto waste organic solid support used to treat palm kernel expeller in the recent Anthropocene

Rawindran H, Syed R, Alangari A, Khoo KS, Lim JW, Sahrin NT, et al.

Environ Res, 2023 Apr 01;222:115352.
PMID: 36716802 DOI: 10.1016/j.envres.2023.115352

The capacity to maximize the proliferation of microalgal cells by means of topologically textured organic solid surfaces under various pH gave rise to the fundamental biophysical analysis of cell-surface attachment in this study. The substrate used in analysis was palm kernel expeller (PKE) in which the microalgal cells had adhered onto its surface. The findings elucidated the relevance of surface properties in terms of surface wettability and surface energy in relation to the attached microalgal growth with pH as the limiting factor. The increase in hydrophobicity of PKE-microalgae attachment was able to facilitate the formation of biofilm better. The pH 5 and pH 11 were found to be the conditions with highest and lowest microalgal growths, respectively, which were in tandem with the highest contact angle value at pH 5 and conversely for pH 11. The work of attachment (Wcs) had supported the derived model with positive values being attained for all the pH conditions, corroborating the thermodynamic feasibility. Finally, this study had unveiled the mechanism of microalgal attachment onto the surface of PKE using the aid of extracellular polymeric surfaces (EPS) from microalgae. Also, the hydrophobic nature of PKE enabled excellent attachment alongside with nutrients for microalgae to grow and from layer-by-layer (LbL) assembly. This assembly was then isolated using organosolv method by means of biphasic solvents, namely, methanol and chloroform, to induce detachment.

Matched MeSH terms: Biofilms
Fulltext The Complex Mechanism of the Salmonella typhi Biofilm Formation That Facilitates Pathogenicity: A Review

Jahan F, Chinni SV, Samuggam S, Reddy LV, Solayappan M, Su Yin L

Int J Mol Sci, 2022 Jun 09;23(12).
PMID: 35742906 DOI: 10.3390/ijms23126462

Salmonella enterica serovar Typhi (S. typhi) is an intracellular pathogen belonging to the Enterobacteriaceae family, where biofilm (aggregation and colonization of cells) formation is one of their advantageous traits. Salmonella typhi is the causative agent of typhoid fever in the human body and is exceptionally host specific. It is transmitted through the fecal-oral route by consuming contaminated food or water. This subspecies is quite intelligent to evade the innate detection and immune response of the host body, leading to systemic dissemination. Consequently, during the period of illness, the gallbladder becomes a harbor and may develop antibiotic resistance. Afterwards, they start contributing to the continuous damage of epithelium cells and make the host asymptomatic and potential carriers of this pathogen for an extended period. Statistically, almost 5% of infected people with Salmonella typhi become chronic carriers and are ready to contribute to future transmission by biofilm formation. Biofilm development is already recognized to link with pathogenicity and plays a crucial role in persistency within the human body. This review seeks to discuss some of the crucial factors related to biofilm development and its mechanism of interaction causing pathogenicity. Understanding the connections between these things will open up a new avenue for finding therapeutic approaches to combat pathogenicity.

Matched MeSH terms: Biofilms
In vitro activity of xanthorrhizol isolated from the rhizome of Javanese turmeric (Curcuma xanthorrhiza Roxb.) against Candida albicans biofilms

Rukayadi Y, Hwang JK

Phytother Res, 2013 Jul;27(7):1061-6.
PMID: 22969012 DOI: 10.1002/ptr.4834

The purpose of this study was to investigate the activity of xanthorrhizol isolated from Curcuma xanthorrhiza Roxb. on Candida albicans biofilms at adherent, intermediate, and mature phase of growth. C. albicans biofilms were formed in flat-bottom 96-well microtiter plates. The biofilms of C. albicans at different phases of development were exposed to xanthorrhizol at different concentrations (0.5 µg/mL-256 µg/mL) for 24 h. The metabolic activity of cells within the biofilms was quantified using the XTT reduction assay. Sessile minimum inhibitory concentrations (SMICs) were determined at 50% and 80% reduction in the biofilm OD₄₉₀ compared to the control wells. The SMIC₅₀ and SMIC₈₀ of xanthorrhizol against 18 C. albicans biofilms were 4--16 µg/mL and 8--32 µg/mL, respectively. The results demonstrated that the activity of xanthorrhizol in reducing C. albicans biofilms OD₄₉₀ was dependent on the concentration and the phase of growth of biofilm. Xanthorrhizol at concentration of 8 µg/mL completely reduced in biofilm referring to XTT-colorimetric readings at adherent phase, whereas 32 µg/mL of xanthorrhizol reduced 87.95% and 67.48 % of biofilm referring to XTT-colorimetric readings at intermediate and mature phases, respectively. Xanthorrhizol displayed potent activity against C. albicans biofilms in vitro and therefore might have potential therapeutic implication for biofilm-associated candidal infections.

Matched MeSH terms: Biofilms/drug effects*; Biofilms/growth & development
Biofilm production by pathogens associated with canine otitis externa, and the antibiofilm activity of ionophores and antimicrobial adjuvants

Chan WY, Hickey EE, Page SW, Trott DJ, Hill PB

J Vet Pharmacol Ther, 2019 Nov;42(6):682-692.
PMID: 31503362 DOI: 10.1111/jvp.12811

Otitis externa (OE) is a frequently reported disorder in dogs associated with secondary infections by Staphylococcus, Pseudomonas and yeast pathogens. The presence of biofilms may play an important role in the resistance of otic pathogens to antimicrobial agents. Biofilm production of twenty Staphylococcus pseudintermedius and twenty Pseudomonas aeruginosa canine otic isolates was determined quantitatively using a microtiter plate assay, and each isolate was classified as a strong, moderate, weak or nonbiofilm producer. Minimum biofilm eradication concentration (MBEC) of two ionophores (narasin and monensin) and three adjuvants (N-acetylcysteine (NAC), Tris-EDTA and disodium EDTA) were investigated spectrophotometrically (OD570nm ) and quantitatively (CFU/ml) against selected Staphylococcus and Pseudomonas biofilm cultures. Concurrently, minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of planktonic cultures were assessed. 16/20 of the S. pseudintermedius clinical isolates were weak biofilm producers. 19/20 P. aeruginosa clinical isolates produced biofilms and were distributed almost equally as weak, moderate and strong biofilm producers. While significant antibiofilm activity was observed, no MBEC was achieved with narasin or monensin. The MBEC for NAC ranged from 5,000-10,000 µg/ml and from 20,000-80,000 µg/ml against S. pseudintermedius and P. aeruginosa, respectively. Tris-EDTA eradicated P. aeruginosa biofilms at concentrations ranging from 6,000/1,900 to 12,000/3,800 µg/ml. The MBEC was up to 16-fold and eightfold higher than the MIC/MBC of NAC and Tris-EDTA, respectively. Disodium EDTA reduced biofilm growth of both strains at concentrations of 470 µg/ml and higher. It can be concluded that biofilm production is common in pathogens associated with canine OE. NAC and Tris-EDTA are effective antibiofilm agents in vitro that could be considered for the treatment of biofilm-associated OE in dogs.

Matched MeSH terms: Biofilms/drug effects; Biofilms/growth & development*
Application of Phenotype Microarray for Profiling Carbon Sources Utilization between Biofilm and Non-Biofilm of Pseudomonas aeruginosa from Clinical Isolates

Ismail NS, Subbiah SK, Taib NM

Curr Pharm Biotechnol, 2020;21(14):1539-1550.
PMID: 32598252 DOI: 10.2174/1389201021666200629145217

BACKGROUND: This is the fastest work in obtaining the metabolic profiles of Pseudomonas aeruginosa in order to combat the infection diseases which leads to high morbidity and mortality rates. Pseudomonas aeruginosa is a high versatility of gram-negative bacteria that can undergo aerobic and anaerobic respiration. Capabilities in deploying different carbon sources, energy metabolism and regulatory system, ensure the survival of this microorganism in the diverse environment condition. Determination of differences in carbon sources utilization among biofilm and non-biofilm of Pseudomonas aeruginosa provides a platform in understanding the metabolic activity of the microorganism.
METHODS: The study was carried out from September 2017 to February 2019. Four archive isolates forming strong and intermediate biofilm and non-biofilms producer were subcultured from archive isolates. ATCC 27853 P. aeruginosa was used as a negative control or non-biofilm producing microorganism. Biofilm formation was confirmed by Crystal Violet Assay (CVA) and Congo Red Agar (CRA). Metabolic profiles of the biofilm and non-biofilms isolates were determined by phenotype microarrays (Biolog Omnilog).
RESULTS AND DISCUSSION: In this study, Pseudomonas aeruginosa biofilm isolates utilized uridine, L-threonine and L-serine while non-biofilm utilized adenosine, inosine, monomethyl, sorbic acid and succinamic acid.
CONCLUSION: The outcome of this result will be used for future studies to improve detection or inhibit the growth of P. aeruginosa biofilm and non-biofilm respectively.

Matched MeSH terms: Biofilms/drug effects; Biofilms/growth & development*
Fulltext Prodigiosin inhibits bacterial growth and virulence factors as a potential physiological response to interspecies competition

Yip CH, Mahalingam S, Wan KL, Nathan S

PLoS One, 2021;16(6):e0253445.
PMID: 34161391 DOI: 10.1371/journal.pone.0253445

Prodigiosin, a red linear tripyrrole pigment, has long been recognised for its antimicrobial property. However, the physiological contribution of prodigiosin to the survival of its producing hosts still remains undefined. Hence, the aim of this study was to investigate the biological role of prodigiosin from Serratia marcescens, particularly in microbial competition through its antimicrobial activity, towards the growth and secreted virulence factors of four clinical pathogenic bacteria (methicillin-resistant Staphylococcus aureus (MRSA), Enterococcus faecalis, Salmonella enterica serovar Typhimurium and Pseudomonas aeruginosa) as well as Staphylococcus aureus and Escherichia coli. Prodigiosin was first extracted from S. marcescens and its purity confirmed by absorption spectrum, high performance liquid chromatography (HPLC) and liquid chromatography-tandem mass spectrophotometry (LC-MS/MS). The extracted prodigiosin was antagonistic towards all the tested bacteria. A disc-diffusion assay showed that prodigiosin is more selective towards Gram-positive bacteria and inhibited the growth of MRSA, S. aureus and E. faecalis and Gram-negative E. coli. A minimum inhibitory concentration of 10 μg/μL of prodigiosin was required to inhibit the growth of S. aureus, E. coli and E. faecalis whereas > 10 μg/μL was required to inhibit MRSA growth. We further assessed the effect of prodigiosin towards bacterial virulence factors such as haemolysin and production of protease as well as on biofilm formation. Prodigiosin did not inhibit haemolysis activity of clinically associated bacteria but was able to reduce protease activity for MRSA, E. coli and E. faecalis as well as decrease E. faecalis, Salmonella Typhimurium and E. coli biofilm formation. Results of this study show that in addition to its role in inhibiting bacterial growth, prodigiosin also inhibits the bacterial virulence factor protease production and biofilm formation, two strategies employed by bacteria in response to microbial competition. As clinical pathogens were more resistant to prodigiosin, we propose that prodigiosin is physiologically important for S. marcescens to compete against other bacteria in its natural soil and surface water environments.

Matched MeSH terms: Biofilms/drug effects*; Biofilms/growth & development
Bacterial biofilms associated skin disorders: Pathogenesis, advanced pharmacotherapy and nanotechnology-based drug delivery systems as a treatment approach

Vyas T, Rapalli VK, Chellappan DK, Dua K, Dubey SK, Singhvi G

Life Sci, 2021 Dec 15;287:120148.
PMID: 34785190 DOI: 10.1016/j.lfs.2021.120148

BACKGROUND: Biofilms are microcolonies of microbes that form communities with a variety of microbes, exhibit the same gene composition but differ in gene expression. Biofilm-associated infections have been in existence for a long, however, biofilm-associated skin disorders have not been investigated much.
OBJECTIVES: Biofilms, which are made mostly of the matrix can be thought of as communities of microbes that are more virulent and more difficult to eradicate as compared to their planktonic counterparts. Currently, several formulations are available in the market which have the potential to treat biofilm-assisted skin disorders. However, the existing pharmacotherapies are not competent enough to cure them effectively and entirely, in several cases.
KEY FINDINGS: Especially with the rising resistance towards antibiotics, it has become particularly challenging to ameliorate these disorders completely. The new approaches are being used to combat biofilm-associated skin disorders, some of them being photodynamic therapy, nanotherapies, and the use of novel drug delivery systems. The focus of attention, however, is nanotherapy. Micelles, solid lipid nanoparticles, quatsomes, and many others are being considered to find a better solution for the biofilm-associated skin disorders.
SIGNIFICANCE: This review is an attempt to give a perspective on these new approaches for treating bacterial biofilms associated with skin disorders.

Matched MeSH terms: Biofilms/drug effects*; Biofilms/growth & development
Fulltext Bacterial Cellulose: Production, Characterization, and Application as Antimicrobial Agent

Lahiri D, Nag M, Dutta B, Dey A, Sarkar T, Pati S, et al.

Int J Mol Sci, 2021 Nov 30;22(23).
PMID: 34884787 DOI: 10.3390/ijms222312984

Bacterial cellulose (BC) is recognized as a multifaceted, versatile biomaterial with abundant applications. Groups of microorganisms such as bacteria are accountable for BC synthesis through static or agitated fermentation processes in the presence of competent media. In comparison to static cultivation, agitated cultivation provides the maximum yield of the BC. A pure cellulose BC can positively interact with hydrophilic or hydrophobic biopolymers while being used in the biomedical domain. From the last two decades, the reinforcement of biopolymer-based biocomposites and its applicability with BC have increased in the research field. The harmony of hydrophobic biopolymers can be reduced due to the high moisture content of BC in comparison to hydrophilic biopolymers. Mechanical properties are the important parameters not only in producing green composite but also in dealing with tissue engineering, medical implants, and biofilm. The wide requisition of BC in medical as well as industrial fields has warranted the scaling up of the production of BC with added economy. This review provides a detailed overview of the production and properties of BC and several parameters affecting the production of BC and its biocomposites, elucidating their antimicrobial and antibiofilm efficacy with an insight to highlight their therapeutic potential.

Matched MeSH terms: Biofilms/drug effects; Biofilms/growth & development
Antimicrobial activity of Lactobacillus spp. isolated from fermented foods and their inhibitory effect against foodborne pathogens

Hussein AO, Khalil K, Mohd Zaini NA, Al Atya AK, Aqma WS

PeerJ, 2025;13:e18541.
PMID: 39790459 DOI: 10.7717/peerj.18541

Lactic acid bacteria (LAB), known for their health benefits, exhibit antimicrobial and antibiofilm properties. This study investigated the cell-free supernatant (CFS) of Lactobacillus spp., particularly L. plantarum KR3, against the common foodborne pathogens S. aureus, E. coli and Salmonella spp. Lactobacillus strains were isolated from cheese, pickles and yoghurt. They were then identified by morphological, physiological and biochemical characteristics and confirmed by 16S rRNA gene sequencing. Culture supernatants from seven lactobacilli isolates showed varying inhibitory activities. Notably, L. plantarum KR3 and L. pentosus had the highest bacteriocin gene counts. L. plantarum KR3 CFS demonstrated significant antibacterial activity, with inhibition zones of 20 ± 0.34 mm for S. aureus, 23 ± 1.64 mm for E. coli, and 17.1 ± 1.70 mm for Salmonella spp. The CFS also exhibited substantial antibiofilm activity, with 59.12 ± 0.03% against S. aureus, 83.50 ± 0.01% against E. coli, and 60. ± 0.04% against Salmonella spp., which were enhanced at the minimum inhibitory concentration (MIC). These results highlighted the potential of L. plantarum KR3 in antimicrobial applications, however, further research is needed to evaluate its viability and functional properties for probiotic use. Additionally, the CFS demonstrated exceptional thermal stability, reinforcing its promise as an antimicrobial agent.

Matched MeSH terms: Biofilms/drug effects; Biofilms/growth & development
Fulltext Anti-biofilm and anti-quorum sensing properties of ethanol and aqueous extracts of Orthosiphon Stamineus and Andrographis Paniculata leaves and stems

Farah Adiba Yang Abd Talib, Hairul Aini Hamzah, Mohammed Imad Al-Deen Mustafa Mahmoud

International Medical Journal Malaysia, 2017;16(11):32-32.
MyJurnal

Quorum sensing controls a wide spectrum of processes and phenotypic
behaviours including biofilm formation that helps in the survival and virulence of
bacteria in hosts. Thus, anti-quorum sensing is suggested to combat bacterial infections.
This study aimed to evaluate the anti-biofilm forming and anti-quorum sensing activities
which may contribute to the anti-bacterial effect of ethanol and aqueous extracts of
Orthosiphon stamineus and Andrographis paniculata leaves and stems. (Copied from article).

Matched MeSH terms: Biofilms
Fulltext The evaluation of Streptococcus mutans content of saliva in patients with recurrent oral ulceration

Al-Ahmad, Basma Ezzat Mustafa, Muhannad Ali Kashmoola, Nur Aini Zakaria

International Medical Journal Malaysia, 2017;16(21):14-14.
MyJurnal

Recurrent oral ulcer is a chronic inflammatory condition characterized by mucosa
ulceration, which was believed to have bacterial etiology. Streptococcus mutans is one of the
bacteria which have been implicated in this case; it is gram-positive bacteria that reside in the
biofilms on the tooth surfaces. The aim of this study was to evaluate Streptococcus mutans content
in saliva of recurrent oral ulcer patients and its role as a prognostic factor. (Copied from article).

Matched MeSH terms: Biofilms
Fulltext Transcriptomic and Genomic Approaches for Unravelling Candida albicans Biofilm Formation and Drug Resistance-An Update

Chong PP, Chin VK, Wong WF, Madhavan P, Yong VC, Looi CY

Genes (Basel), 2018 Nov 07;9(11).
PMID: 30405082 DOI: 10.3390/genes9110540

Candida albicans is an opportunistic fungal pathogen, which causes a plethora of superficial, as well as invasive, infections in humans. The ability of this fungus in switching from commensalism to active infection is attributed to its many virulence traits. Biofilm formation is a key process, which allows the fungus to adhere to and proliferate on medically implanted devices as well as host tissue and cause serious life-threatening infections. Biofilms are complex communities of filamentous and yeast cells surrounded by an extracellular matrix that confers an enhanced degree of resistance to antifungal drugs. Moreover, the extensive plasticity of the C. albicans genome has given this versatile fungus the added advantage of microevolution and adaptation to thrive within the unique environmental niches within the host. To combat these challenges in dealing with C. albicans infections, it is imperative that we target specifically the molecular pathways involved in biofilm formation as well as drug resistance. With the advent of the -omics era and whole genome sequencing platforms, novel pathways and genes involved in the pathogenesis of the fungus have been unraveled. Researchers have used a myriad of strategies including transcriptome analysis for C. albicans cells grown in different environments, whole genome sequencing of different strains, functional genomics approaches to identify critical regulatory genes, as well as comparative genomics analysis between C. albicans and its closely related, much less virulent relative, C. dubliniensis, in the quest to increase our understanding of the mechanisms underlying the success of C. albicans as a major fungal pathogen. This review attempts to summarize the most recent advancements in the field of biofilm and antifungal resistance research and offers suggestions for future directions in therapeutics development.

Matched MeSH terms: Biofilms
Fulltext Mechanical and physical properties of gellan gum (GG) biofilm: effect of glycerol

Razali, M.H., Ismail, N.A., Osman, U.M., Amin, K.A.M.

ASM Science Journal, 2018;11(101):158-165.
MyJurnal

The aim of this work was to investigate the effect of glycerol concentration on mechanical
and physical properties of gellan gum (GG) biofilm. The biofilm was prepared using solvent
casting method and the effective glycerol concentration was found to be within 30-50%
w/w (based on GG weight). At 60 and 70 w/w% of glycerol, the films started to distort
because the films was flexible and brittle. As glycerol concentration was increased the tensile
strength (TS) and Youngs modulus (E) of films decreased. Somehow, elongation at break
(EAB), water vapor transmission rate (WVTR) and swelling of films was increased. Glycerol
plasticized GG biofilm was thermally stable and flexible, proposed its can be exploited as
film-forming material and with optimized glycerol concentration it has good mechanical and
physical properties for edible biofilm.

Matched MeSH terms: Biofilms
Nicotine enhances the thickness of biofilm and adherence of Candida albicans ATCC 14053 and Candida parapsilosis ATCC 22019

Gunasegar S, Himratul-Aznita WH

FEMS Yeast Res., 2019 Mar 01;19(2).
PMID: 30476044 DOI: 10.1093/femsyr/foy123

Candida albicans ATCC 14053 and Candida parapsilosis ATCC 22019 hyphal-wall protein 1 (HWP1) are involved in hyphae formation and pathogenesis. The transcriptional agglutinin-like sequence 3 (ALS3) genes in both species are responsible for the development of biofilm and colonization on tooth surfaces. Therefore, we investigated the expression of HWP1 and ALS3 quantitatively in C. albicans and C. parapsilosis and examined the biofilm structure upon exposure to various nicotine concentrations. In vitro, biofilms of Candida species were developed directly on slides using the Lab-Tek Chamber Slide System and visualized by confocal laser scanning microscopy. Quantitative real-time polymerase chain reaction was used to measure HWP1 and ALS3 expression in C. albicans ATCC 14053 and C. parapsilosis ATCC 22019. The results indicated that nicotine multiplied the number of yeast cells and increased the extracellular polysaccharides of Candida species. We also found that 1-2 mg/mL nicotine could enhance the formation of biofilm. The findings also revealed that the expression of HWP1 and ALS3 in Candida species were increased as the nicotine concentration increased. Therefore, nicotine influences the biofilm development of oral-associated C. albicans ATCC 14053 and C. parapsilosis ATCC 22019.

Matched MeSH terms: Biofilms
Effects of Salvadora persicaExtract on the bacterial population in single-species biofilm

Nordin Fatin-Majdina, Haji Abd Rahim Zubaidah, Mohd Bakri Marina, Abd Razak Monica@Munirah

Sains Malaysiana, 2014;43:1889-1893.

The effect of S. persica extract on the population of bacteria in single-species biofilm was investigated. An artificial mouth (NAM) system was used for the development of biofilm. In one experiment, aqueous extract of S. persica at sub-MIC concentration (5 mg/mL) was first pumped into the NAM system to treat the experimental pellicle on glass beads before inoculating it with the bacteria (Strep. mitis, Strep. mutans and Strep. sanguinis). This would resemble using the aqueous extract of S. persica before meals. In another experiment, the aqueous extract of S. persica was pumped into the NAM system after the bacterial inoculation and this would resemble using it after meals. In both experiments, 24 h biofilms were allowed to form. The bacterial population of the biofilms was determined and expressed as colony forming unit per mL (cfu mL-1). For negative control, sterilized distilled water was used whereas for positive control, commercial Listerine. It was found that the population of Strep. mitis, Strep. mutans and Strep. sanguinis in the respective biofilms for both experiments involving treatment with S. persica extract or Listerine was significantly reduced by more than 70% (p<0.05) when compared with the negative control. Comparing the effect of S. persica with Listerine on the bacterial population of the biofilms when used either before or after meal showed that S. persica is slightly less effective towards S. sanguinis before meal and towards S. mutans after meal (p<0.05). This study suggests that the efficiency of the antibacterial effect of S. persica is species-related and by its way of usage.

Matched MeSH terms: Biofilms
Inhibition of consortium sulfate reducing bacteria from crude oil for carbon steel protection

Nur Akma Mahat, Norinsan Kamil Othman, Mohd Nazri Idris, Fathul Karim Sahrani

Sains Malaysiana, 2015;44:1587-1591.

The efficiency of cetyltrimethylammonium bromide (CTAB) to reduce the activity of consortium bacteria consisting of
sulphate-reducing bacteria (C-SRB) has been investigated on variable concentration by weight loss test, potentiodynamic
polarization and diffusion disk methods. C-SRB was isolated from tropical crude oil of Malaysian offshore. Biofilm analysis
was also evaluated by variable pressure scanning electron microscopy (VPSEM). Weight loss and potentiodynamic
polarization analyses showed that CTAB is able to inhibit the biocorrosion process and their inhibition efficiency had
reached to 85 and 65% at 300 ppm CTAB, respectively. Increasing of CTAB efficiency as a function of concentration was
also supported by diffusion disk analysis. Biofilm analysis showed that less of C-SRB and their metabolic by-product had
been observed. It was concluded that CTAB was able to reduce the C-SRB activity and prevent biocorrosion process on
carbon steel surface.

Matched MeSH terms: Biofilms
Intraoral appliances for in situ oral biofilm growth: a systematic review

Abdullah N, Al-Marzooq F, Mohamad S, Abd Rahman N, Chi Ngo H, Perera Samaranayake L

J Oral Microbiol, 2019;11(1):1647757.
PMID: 31489127 DOI: 10.1080/20002297.2019.1647757

Background: Oral biofilms are the root cause of major oral diseases. As in vitro biofilms are not representative of the intraoral milieu, various devices have been manufactured over the years to develop Appliance Grown Oral Biofilm (AGOB). Objective: To review various intraoral appliances used to develop AGOB for microbiological analysis, and to judge the optimal means for such analyses. Design: Four databases (PubMed, Science Direct, Scopus and Medline) were searched by two independent reviewers, and articles featuring the key words 'device' OR 'splint' OR 'appliance'; 'Oral biofilm' OR 'dental plaque'; 'in vivo' OR 'in situ'; 'Microbiology' OR 'Bacteria' OR 'microbiome'; were included. The standard Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) were adopted for data gathering. Results: Of the 517 articles which met the initial inclusion criteria, 24 were deemed eligible for review. The age of the AGOB, sampled at various intervals, ranged from 30 min to 28 days. The most commonly used microbiome analytical methods were fluorescence microscopy, total cell count using conventional, and molecular tools including Next Generation Sequencing (NGS) platforms. Conclusions: No uniformly superior method for collecting AGOB could be discerned. NGS platforms are preferable for AGOB analyses.

Matched MeSH terms: Biofilms
An in vitro study of a novel quaternary ammonium silane endodontic irrigant

Daood U, Parolia A, Elkezza A, Yiu CK, Abbott P, Matinlinna JP, et al.

Dent Mater, 2019 09;35(9):1264-1278.
PMID: 31201019 DOI: 10.1016/j.dental.2019.05.020

OBJECTIVE: To analyze effect of NaOCl+2% quaternary ammonium silane (QAS)-containing novel irrigant against bacteria impregnated inside the root canal system, and to evaluate its antimicrobial and mechanical potential of dentine substrate.
METHODS: Root canal was prepared using stainless steel K-files™ and ProTaper™ and subjected to manual and ultrasonic irrigation using 6% NaOCl+2% CHX, 6% NaOCl+2% QAS and saline as control. For confocal-microscopy, Raman spectroscopy and SEM analysis before and after treatment, Enterococcus faecalis cultured for 7 days. Raman spectroscopy analysis was done across cut section of gutta percha/sealer-dentine to detect resin infiltration. Indentation of mechanical properties was evaluated using a Berkovich indenter. The contact angle of irrigants and surface free energy were evaluated. Mineralization nodules were detected through Alazarin red after 14 days.
RESULTS: Control biofilms showed dense green colonies. Majority of E. faecalis bacteria were present in biofilm fluoresced red in NaOCl+2% QAS group. There was reduction of 484cm-1 Raman band and its intensity reached lowest with NaOCl+2% QAS. There was an increase in 1350-1420cm-1 intensity in the NaOCl+2% CHX groups. Gradual decrease in 1639cm-1 and 1609cm-1 Raman signal ratios were seen in the resin-depth region of 17μm>, 14.1μm> and 13.2μm for NaOCl+2% QAS, NaOCl+2% CHX and control groups respectively. All obturated groups showed an intact sealer/dentine interface with a few notable differences. 0.771 and 83.5% creep indentation distance for NaOCl+2% QAS ultrasonic groups were observed. Highest proportion of polar component was significantly found in the NaOCl+2% QAS groups which was significantly higher as compared to other groups. Mineralized nodules were increased in NaOCl+2% QAS.
SIGNIFICANCE: Favorable antimicrobial and endodontic profile of the NaOCl+2% QAS solution might suggest clinical use for it for more predictable reduction of intracanal bacteria.

Matched MeSH terms: Biofilms

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